ANCHORAGE, Alaska— The Center for Biological Diversity filed a formal petition today to protect Iliamna Lake seals under the Endangered Species Act. These unique, little-understood seals are one of only five seal populations in the Northern Hemisphere living exclusively in freshwater, and the only American freshwater seals; other freshwater seals are found in Northern Quebec, Finland and Russia. Iliamna Lake seals live in the eastern half of Alaska’s largest, deepest body of freshwater, in a pristine and unique wilderness area located some 200 miles southwest of Anchorage that’s home to the world’s largest run of sockeye salmon. The seals are threatened by mine development and climate change.

“Salmon are crucial to the Iliamna Lake ecosystem, and especially the lake’s native seals,” said Kiersten Lippmann, a biologist with the Center. “There’s nowhere else on Earth where sockeye salmon spawn in such abundance. Salmon are a critical food for the seals, and once they spawn out and decompose they’re a vital energy source for the whole region.”

Like “Illie,” the legendary Iliamna Lake “monster” that’s fabled to break the lake’s surface on occasion, Iliamna Lake seals have been shrouded in mystery. The seals were previously assumed to be visiting harbor seals from Bristol Bay, but recent aerial surveys have confirmed local observations that the seals are present on the lake year-round, where they pup and raise young. Locals say the lake seals are larger, fatter and darker in color than saltwater seals; they sport a unique fur pattern and have oilier pelts. Locals also speak of under-ice caves where many of the seals spend the winter, which hide them from aerial surveys over the dark winter months.

Until recently there has been little scientific interest in these seals, and as a result scientists remain unsure about many aspects of their biology and behavior. Research is ongoing to determine the seals’ origins, with evidence to date suggesting that the Iliamna Lake seals are a distinct population segment of Pacific harbor seals.

Iliamna Lake seals face growing threats of extinction due to proposed large-scale open-pit copper and gold mines, especially the “Pebble Project,” which would be located just 17 miles upstream from the seals’ preferred haul-out spots. The seals are also threatened by climate change. Both threats will degrade and eliminate important salmon-spawning habitat and have major negative impacts on water and habitat quality.

“A huge open-pit mine like the Pebble Project could wipe out the Iliamna Lake seal,” said Lippmann. “Activities related to Pebble Project would pollute the water, destroy salmon-spawning habitat, and disturb the seals during vulnerable pupping and molting periods. In the event of a mine failure or accident, pollutants and waste from the mine would cause irreversible harm that would continue for centuries.”

Human-caused climate change also threatens Iliamna Lake seals and the salmon on which they depend. Ocean acidification and climate warming are progressing rapidly in the Bering Sea; these changes threaten the survival of calcifying plankton that oceangoing salmon need for food. Climate change will also increase precipitation and raise water temperatures, which could eliminate suitable spawning habitat for salmon and wash away their eggs and fry from spawning streams, killing the young.

“When the salmon are gone, the Iliamna Lake seals will likely starve,” said Lippmann. “Iliamna Lake seals are able to thrive in the lake because of the year-round availability of nutritionally dense fish like salmon. Climate change will squeeze the salmon that spawn in Iliamna Lake area from two sides, by degrading habitat in both the marine and the freshwater environments. As a result, the hugely productive salmon runs of Iliamna Lake watershed may soon be a thing of the past.”

Climate change will also cause shifts in the timing of salmon runs. In order to coincide with peak numbers of salmon in the lake, Iliamna Lake seals give birth to pups about one month later than saltwater harbor seals in nearby Bristol Bay. Shortly after the pups are weaned, the seals haul out on land for their annual molt in August. Right now these energetically demanding times in the seals’ life cycles are perfectly timed so that there are ample salmon in the lake to provide food for hungry seals. A climate-change-caused shift in the timing of salmon runs would disrupt this balance.

Protection under the Endangered Species Act would prompt conservation of the Iliamna Lake seal, along with greater research into this enigmatic species. The Act would require federal agencies to ensure their actions do not harm Iliamna Lake seals. Federal permits for large-scale mining projects like the Pebble Project in the Bristol Bay area would have to consider impacts to Iliamna Lake seals from any action that would result in disturbance of the seals, degradation of their habitat, or elimination or reduction of the all-important salmon of the Iliamna Lake region.

The National Oceanic and Atmospheric Administration must respond to the Center’s petition in 90 days and determine whether listing is warranted within one year.

The Center for Biological Diversity is a national, nonprofit conservation organization with more than 450,000 members and online activists dedicated to the protection of endangered species and wild places.